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1. Field of the Invention
This invention is directed to manually held and manually manipulated writing implements with means to conform to the hand of the user and to methods for making thereof.
2. Description of the Related Art
Various well known writing instruments have found common use and appeal. Examples include conventional hexagonal cross-sectional pencil shaped to reduce unintended rolling and slippage, and round cross-sectional pens having polymeric slip-reducing materials for the shells thereof and having cap clips for reducing rolling and for attaching to pockets. Generally, these designs have not been as ergonomically well designed for prolonged periods of use based on the way that such pencils and pens are conventionally held during extended writing periods. Additionally, many of these prior pens have a tendency to roll on desk tops.
Prior attempts to improve the ergonomic designs of such pens and pencils have for example lead to the use of various scooped portions for receiving the index finger or have lead to non-uniform curvatures. For pencils, the bodies of which are consumed during use, the use of a non-uniform shape would undesirably result in frequently changing grip configurations following sharpening. Also, various ergonomic pencil configurations would not be suitable for being sharpened in conventional pencil sharpeners. Prior writing instruments have been disclosed in Hochstetler U.S. Pat. No. 5,228,794 issued Jul. 20, 1993 which discloses a writing instrument having groove spirals around a shell; Pleasants U.S. Design Pat. No. 136,595 issued Nov. 2, 1943 which discloses a pen holder Lamb U.S. Design Pat. No. 202,395 issued Sep. 21, 1965 which discloses a holder for a writing instrument having a non-uniform cross-section; Zeckendorf U.S. Design Pat. No. 18,032 issued Jan. 24, 1888 which discloses a lead pencil having a pair of flat sides and a curved side; Eckert et al U.S. Design Pat. No. 22,524 issued Jun. 13, 1893 which discloses a pen holder having spirals; Fuchs U.S. Design Pat. No. 191,341 issued Sep. 12, 1961 which discloses a mechanical pencil; Anderson U.S. Design Pat. No. 237,705 issued Nov. 18, 1975 which discloses a pen; Johansson U.S. Design Pat. No. 323,350 issued Jan. 21, 1992 which discloses a pen; Tucker U.S. Design Pat. No. 31,072 issued Jun. 27, 1899 which discloses a pencil having spirally formed ribs; Kageyama et al. U.S. Pat. No. 5,090,831 issued Feb. 25, 1992 which discloses a writing instrument; Kageyama U.S. Pat. No. 5,207,522 issued May 4, 1993 which discloses a mechanical pencil; and Kageyama et al. U.S. Pat. No. 5,236,270 issued Aug. 17, 1993 which discloses a writing tool; all of which are incorporated herein by reference in their entireties.
The non-uniform design of some of these designs could result in inefficient packaging; some of the uniform designs do not provide for ease in picking up the writing utensil from a resting position; and some of the spiral designs are too tightly wound to provide for comfortable long term writing.
U.S. Pat. No. 5,893,671 (xe2x80x9cPatent ""671xe2x80x9d) issued on Apr. 13, 1999 to the instant inventor discloses a writing instrument with a triangular cross section and a uniform spiral twist of the cross section axially along the length of the instrument. However the pitch of the spiral twist is limited to between 150 and 210 degrees total along the overall length of the instrument. As disclosed in Patent ""671, the ergonomic alignment of the surfaces of the writing instrument with the parts of the right hand were achieved with an overall twist of between 150 and 210 degrees over the total instrument length, but only when the direction of twist was counter-clockwise, traversing longitudinally away from the viewer. Similarly, the same ergonomic result was achieved if held in the left hand when the direction of twist was clockwise. Patent ""671 failed to address the degree of twist necessary to obtain an ergonomic result for a writing instrument with a clockwise twist held in the right hand, or similarly for an instrument with a counter-clockwise twist held in the left hand.